I would be surprised if either party picked up or lost more than 10 seats, something like that. Democrats need a 25 seat net gain to get their majority back in the House. And I think that's awfully hard. They may pick up five or 10; they may lose five or 10. I don't see a lot of change in the House of Representatives right now.

More likely is that the redistricting that emerges from the decennial census will change sometimes significantly the makeup of a lawmaker's constituency.

Some Democrats will find themselves with more blacks and Hispanics as constituents while some Republicans may have more Democrats in their reshaped districts, Cook said.